Ankle joint for artificial limbs



Jimi956 c. WooDALL ANKLE JOINT FOR ARTIFICIAL LIMBS Filed Oct. 20, 1952 INVENTOR.

rl`his invention relates generally to artificial limbs and relates more particularly to improvements in ankle joints therefor, this application being a continuation-in-part of my copending application for Artificial Limb, Serial No. 49,719, tiled September 17, 1943, now Patent No. 2,629,105.

it is an object of the invention to provide in an artiiicial limb an ankle joint wherein the articulated parts faithfully simulate the movements and actions of the corresponding natural elements.

Another object of the invention is to provide an articial liinb wherein the ankle joint is provided with a ball and socket arrangement which carries substantially the full weight of the user.

Stili another object of the invention is to provide a device of this character having a shock absorbing control id States arent cushion which limits the movements of the socket and permits the Vtoot to accommodate itself to uneven surfaces.

A further object of the invention is to provide an artilicial limb having an ankle joint wherein there is a limited torque and lateral action therein.

A still further object of the invention is to provide simple means for retaining the shock absorbing cushion in position so that it will not work out of the joint.

A still further object of the invention is to provide means for adjusting the articial foot relative to the plane of swing ot' the ankle joint, which plane of swing corresponds to the plane of swing of the knee joint.

Another object of the device is to provide an artificial limb of this character that is simple in construction, smooth in action, and easy to assemble.

@ther objects and advantages of the invention will be brought out in the following part of the specification.

Referring to the drawings, which are for illustrative purposes only,

Fig. l is a perspective view showing an artificial limb embodying the invention;

Fig. 2 is an enlarged partial section of the ankle joint;

Fig. 3 is a section taken on line 3-3 of Fig. 2; and

Fig. 4 is a perspective view of the shock absorbing and control cushion.

Referring to Fig. l, there is shown an artificial limb having a thigh member i0 connected by a knee unit, indicated generally at l, to the upper end of a shank member or shin ft2, which in turn is connected to a foot 13 by an ani-:ie unit, indicated generally at 14.

Referring to Figs. 2, 3 and 4, the ankle unit includes a shank plate l5 secured to the adjacent end of the shank l2 by means of a bolt 16 and nut 17 located in a recess i3 in the shank. The shank plate is further secured to the shank by means of screws 19 which prevent rotation oi the shank plate relative to the adjacent end of the shank. rhe shank plate is provided with a recess Z0 adjacent the center thereof, in which is disposed a clevis 2i formed integral with the adjacent end of the bolt 16. Between the side members of the clevis is disposed a ball 22. secured between said clevis members by a rivet 23.

The foot 13 is provided with a foot plate 24 secured to the foot by screws 25 and provided with a forward extension 24a. The foot plate also has an opening 26 therein, which tapers upwardly and outwardly at the front and back, and in which is received a bolt 27 having an eye 23 with a bearing 29 which engages the ball 22 t0 thereby form a universal ball and socket connection. The bolt 27 is secured by a nut 39 which is disposed in a recess 31 in the bottom of the foot i3.

The shank plate is provided adjacent the front end with a transversely extending recess 32 which is concave in cross section and defined at the front by a depending portion 33. The extension 24a of the foot plate 24 is also provided with a transverse recess 34 which corresponds to the recess 32. The recesses 32 and 34 receive a transversely extending cylindrical instep portion 36 of a shock absorber and control cushion indicated generally at 37. The cushion also includes a pair of aligned cylindrical torque and lateral action portions 38 which are spaced apart to provide an opening 39 in which the ball and socket joint is received. The cylinders 36 and 38 are formed of any suitable resilient material such as rubber, and are connected together by a web 40. The opposite sides of the cylinders 3S are also Connected together by a web el.

The shank plate 15 is provided with recesses 42 on opposite sides of the recess Ztl, and the foot 1.3 is provided with corresponding recesses 43. The recesses 42 and 43 are concave in cross section and receive the respective cylindrical portions 33 of the cushion 37. The outer end of each of the recesses l2 is provided with a llange 44 which engages the respective sides of the portion 3S and retain the cushion 37 in position.

The rear end portion of the shank plate 15 is provided with a recess lo which has an opening in the bottom thereof in register with the recess 47 in the shank tor reception of one end of a bumper 48. The opposite end of the bumper is received in a recess 49 in the heel of the foot 13, said bumper being of any suitable resilient material such as rubber or the like.

in use the portion 36 will yield under compressive action between the bottoms of the recesses 32 and 34, and the portions 33 permit limited torque action and lateral action which, together with the ball and socket, provide the various actions required and effect close simulation of the actions of the natural ankle. It has been found that this mechanism permits the foot to accommodate itself to uneven surfaces in a most natural manner.

in the present ankle joint, the universal ball and socket is adapted to be the primary weight-carrying part. The shank plate l5 is carried by the shoulders at the upper end of the clevis 2l and the foot plate 24 carries the Weight transferred through the bail and socket connection.

it is desirable to have the ankle swing in the same plane as the plane of swing of the knee joint. However, the foot of the individual does not necessarily have the same alignment. 'With some individuals the toe may be turned inwardly, while in others, it might be turned outwardly. The present invention provides means whereby the ankle joint will swing in the saine plane as the plane of swing of the knee joint while, at the same time, positioning the foot in accordance with the natural position of the individuals foot. This positioning of the foot is accomplished by attaching the foot plate 2d to the foot member 13 so that said foot member will have the normal position without interfering with the position of the ball and socket joint of the ankle with respect to its plane of swing.

l claim:

l. An ankle joint for artificial limbs including a leg section and a foot member, comprising: a universal joint for connecting said leg section and foot member ltogether in spaced relation; a resilient cushion disposed in said space, said cushion comprising a cylindrically shaped instep portion disposed forwardly of the ball and socket jointy and extending transversely of said foot member; and a pair of cylindrically shaped torque action portions disposed adjacent each side of said joint, the parts of said cushion being connected together by a web.

2. In an ankle joint for articial limbs including a leg section and a foot member: a universal joint connecting the foot member and leg section together in spaced relation to each other; and a cushion disposed in said space, said cushion being resilient and comprising an elongated portion extending transversely of the foot member from side tol side thereof and disposed forwardly of said joint; and torque action cushion portions disposed adjacent each side of said joint, said cushion portions being spaced rearwardly of said elongated portion and being adapted to contact both the leg section and the foot member at all times, the parts of said cushion being connected together by web means.

3. A resilient cushion for the ankle joint of an artificial limb comprising: an elongated portion; a pair of members longitudinally aligned in parallelism with the elongated portion and spaced therefrom, said members being spaced apart from each other; and web portions connecting the members to the elongated portion and a second Web member connecting said members together.

4. A resilient cushion for the ankle joint of an artificial limb, comprising: an elongated cylindrical portion; a pair of cylindrical members longitudinally aligned with each other and in parallelism with the elongated portion and spaced therefrom, said members being spaced apart from each other; and web portions connecting the members to the elongated portion and a second web member connecting said pair of members together.

5. In an ankle joint for artificial limbs having a shank and a foot member; a shank plate for attachment to one end of the shank, said shank plate having a transverse recess facing the foot member; a foot plate attached to the foot member and having a transverse recess facing the transverse recess of the shank plate; a universal joint adapted to connect the toot member and the adjacent end of the shank in spaced relation to each other; a cushion of resilient material disposed between the plates and including an elongated cylindrical instep portion received in the recess of the shank plate forwardly of said joint, and cylindrical torque action portions disposed at opposite sides of the joint, said torque action portions being in substantially longitudinal alignment with each other; and web members connecting the various portions of the cushion together.

6. In an ankle joint for artificial limbs having a shank and a foot member; ka shank plate for attachment to one end of the shank,l said shank plate having a transverse recess facing the foot member; a foot plate attached to the foot member and having a transverse recess facing the transverse recess of the shank plate; an articulate joint adapted to connect the foot member and the adjacent end of the shank in spaced relation to each other; a cushion of resilient material disposed between the plates and including an elongated cylindrical instep portion received in the recess of the shank plate forwardly of said joint, and cylindrical torque action portions disposed at opposite sides of the joint, said torque action portions being in substantially longitudinal alignment with each other; and web members connecting the various portions of the cushion together.

7. A resilient cushion for the ankle joint of an artificial limb comprising: an elongated portion; a pair of torque action members longitudinally aligned in parallelism with the elongated portion and spaced therefrom, said mem bers being spaced apart from each other; and web portions connecting the members to the elongated portion and a second web member connecting said members together.

References Cited'in the file of this patent UNITED STATES PATENTS 630,630 Rice Aug. 8, 1899 1,001,641 Harrison Aug. 29, 1911 FOREIGN PATENTS 421,482 Great Britainl Dec. 21, 1934 

